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What is the ONTAP e0S interface?

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Applies to

  • AFF A900, AFF A800, AFF A700s, AFF A700, AFF A400, AFF A320, AFF A250, AFF A220, AFF A200, AFF C190
  • FAS9000, FAS8700, FAS8300, FAS8200, FAS500f, FAS27xx, FAS26xx


The e0S interface is an interface in newer FAS and AFF storage systems.

Conceptually, e0S is an ONTAP interface on a node that is used for internal communication with its service processor (SP) or baseboard management controller (BMC).

  • It is auto-configured with hard-coded IP addresses in the 192.0.2.x subnet.
  • On most platforms, it is used for SP FW updates and error condition reporting.
  • On many BMC-based platforms, this internal subnet is used for HW-assisted storage failover, as well (since both nodes' e0S interfaces and BMCs can see each other internally).
HA Systems Details
  • AFF A700/FAS9000
  • AFF A300/FAS8200
  • AFF A220/FAS27xx
  • AFF A200/FAS26xx
  • AFF C190
  • e0S is implemented as a VLAN on the e0M interface: e0M-16
  • e0M-16 (specifically using VLAN tag 16) is sharing the same physical internal Ethernet port as e0M, but is restricted to only communicate with its local SP or BMC, also on VLAN tag 16.
  • e0M-16 is always hard-coded to The SP or BMC eth0.16 interface is always configured with
  • e0M-16 is in its own IPspace (OS2SP).
  • HW-assisted failover does not use e0M-16 when communicating with the partner's SP or BMC.
  • AFF A900
  • AFF A800
  • AFF A700s
  • AFF A400
  • AFF A320
  • AFF A250
  • FAS8700
  • FAS8300
  • FAS500f
  • A private and internal Ethernet-switched subnet exists between both ONTAP HA partners and both BMCs:
    • ONTAP interface: e0S
    • BMC interface: Either eth0 or eth1, depending on the platform model
  • Uses subnet with statically-assigned IP addresses for all interfaces
  • Features such as HW-assisted failover, ONTAP <-> BMC communications (IPMI), and BMC FW updates are performed over this private network.
  • HW-assisted takeover is not configurable – it uses statically-assigned addresses (see the table, below)

The IP addressing is static and automatically configured on all related Ethernet interfaces:

Controller e0S Address/Mask BMC Address/Mask

Additional Information



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